Adjust cache-repo CI stage run conditions
The cache-repo CI stage was failing on gitlab-org/gitlab-foss because the CI_REPO_CACHE_CREDENTIALS wasn't defined.
We now adjust the restriction of this CI stage to run under two conditions:
- On a schedule
- When CI_REPO_CACHE_CREDENTIALS is defined.
That way, dev.gitlab.org and other instances can produce their own caches if necessary.
Also this changes the GIT_STRATEGY to none to reduce the overall size of the pack files and avoid the pre-clone step. The current cache crept up to close to a 1 GB as a result of an incremental update.
Edited by Stan Hu